Wrap-around article carriers are used to enclose a plurality of similarity shaped containers such as beverage containers. Typically, such an article carrier comprises a sleeve with at least partially open ends. The sleeve is formed by folding a blank comprising a plurality of panels which become the top, bottom and sides of the sleeve. Usually, such a blank will have a generally rectangular shape with end portions of the blank cooperating to form a continuous sleeve for enclosing articles. The blank is constructed from a material that is suitable for folding while possessing sufficient rigidity and strength for use in an article carrier. Paperboard is a common material used in manufacture of article carrier sleeves.
Article carrier sleeves of the kind described above may be rapidly assembled to enclose articles by using machinery designed to form a sleeve from a blank. Such machinery carries out the steps of folding the blank into a sleeve surrounding the articles and engaging cooperating locking means on the blank to maintain the sleeve in a tensioned state around the articles.
Having at least partially open ends of the sleeve reduces the amount of material required in constructing the article carrier and the number of steps required to form the carrier. However, the absence of material at the ends of the sleeve makes it possible for articles retained within the sleeve to move outwards through the end of the sleeve and possibly be lost, unless some means is provided for limiting such outward movement. Outward movement of articles retained within the sleeve is a particular problem where the articles are not of uniform shape such as where the articles are bottles having a narrow neck portion, a broad middle portion, and a base portion tapering inwards from the middle portion to the bottom of the bottle.
The sleeves described in U.S. Pat. Nos. 5,094,347 and 5,107,986 seek to overcome the above described disadvantages by providing integral article retaining means within the sleeve which are essentially 3-dimensional protuberances formed in the bottom of the sleeve adjacent open ends of the sleeve and positioned to be adjacent to the base of articles retained within the sleeve so as to prevent outward movement of the articles towards the open ends of the sleeve. In each case, the bottom of the sleeve is formed from overlapping end portions or panels of the blank with the outer bottom panel including a retaining flap which is forced through a corresponding opening in the inner bottom panel and is folded within the resulting sleeve to form the 3-dimensional article retaining means. Where it is desired to form embodiments of these inventions on automatic packaging machinery, such machinery must include a movable punch or rod element that forces the retaining flap through the corresponding opening in the inner bottom panel.
Another example of an article retaining sleeve that requires the use of a movable punch or rod element to form a three-dimensional protuberance within the sleeve to act as a retaining means is that described in copending U.S. patent application Ser. No. 08/020,752 of Gungner and Zimmerman. The process of forming the sleeves described in U.S. application Ser. No. 08/020,752 and U.S. Pat. Nos. 5,094,347 and 5,107,986, as well as the machinery required for doing so, is more complex than is required in forming other sleeves known in the art that lack such three-dimensional protuberances as retaining means. Examples of sleeves of the latter type are those provided under the trademark JAK-ET-PAK as well as the sleeve of Sutherland et al described in U.S. Pat. No. 4,708,284, wherein a male locking tab of the blank is on an outer overlapping bottom panel of the sleeve. In automated packaging machinery, the male locking tab is first folded and then is pushed by means of a ramp over which the blank travels, through a corresponding opening (such as a slit) in an inner overlapping bottom panel of the sleeve so that the male tab extends within the sleeve and is engaged therein. The male tab serves as a secondary locking element and the tab may be positioned within the sleeve so as to separate adjacent articles held within the sleeve. The kind of automated packaging machinery used to form such sleeves does not require a punch or rod element to push the male locking tab through the corresponding opening.